The detection of specific nucleic acid sequences present in a biological sample is important for identifying and classifying microorganisms, diagnosing infectious diseases, detecting and characterizing genetic abnormalities, identifying genetic changes associated with cancer, studying genetic susceptibility to disease, and measuring response to various types of treatment. A common technique for detecting and quantitating specific nucleic acid sequences is nucleic acid hybridization.
Various hybridization methods are available for the detection and study of nucleic acids. In a traditional hybridization method, the nucleic acids to be identified are either in a solution or affixed to a solid carrier. The nucleic acids are detected using labelled nucleic acid probes which are capable of hybridizing to the nucleic acids. Recently, new hybridization methods have been developed to increase the sensitivity and specificity of detection. One example is the hybrid capture method described in U.S. application Ser. No. 07/792,585. Although these new hybridization methods offer significant improvements over the traditional methods, they still lack the ability to fully discriminate between highly homologous nucleic acid sequences.
It is therefore an object of the present invention to provide a hybridization method which is not only rapid and sensitive, but is also highly specific and capable of discriminating highly homologous nucleic acid target sequences.